Lens attachment for flash-light photographing

ABSTRACT

In an automatic flash camera having a lens with a rotatable focusing ring, a lens attachment coacts with the focusing ring to control the camera. In the attachment, a mounting arrangement detachably mounts the attachment to the end of the lens. An interconnecting arrangement, rotatably mounted on the mounting arrangement, engages the focusing ring to move therewith. A variable resistance system is mounted on the two arrangements and is varied by movement of the interconnecting arrangement relative to the mounting arrangement. The variable resistance system includes an adjustable member which is movable between a number of positions. In one position the variable resistance system exhibits one range of resistances corresponding to one type of lens when the interconnecting arrangement is moved. In other positions the variable resistance system exhibits other ranges of resistances each corresponding to lenses of other aperture ratios and focal lengths. An electrical system connected to the variable resistance system responds to the value of the resistance exhibited and controls the diaphragm of the camera for automatic flashlight photography.

United States Patent [1 1 Mitani et al.

11] 3,738,240 June 12, 1973 [21] Appl. No.: 184,351

[30] Foreign Application Priority Data Oct. 2, 1970 Japan 45/86939 [58]Field of Search 95/11 L, 11 R, 11.5 R,

95/64 A, 64 D, 10 C, 10 CD; 240/1.3

US. Cl. 95/11 R, 95/10 C, 95/64 A [56] References Cited UNITED STATESPATENTS 3,505,938 4/1970 Zobel et a1 95/10 C 3,504,602 4/1970 Kiper etal. 95/64 D X FOREIGN PATENTS OR APPLICATIONS 1,509,742 1/1968 France95/10 C Int. Cl. G031) 7/20, G03b 7/16 Primary Examiner-Robert P.Greiner Attorney-Toren and McGeady [57] ABSTRACT In an automatic flashcamera having a lens with a rotatable focusing ring, a lens attachmentcoacts with the focusing ring to control the camera. In the attachment,a mounting arrangement detachably mounts the attachment to the end ofthe lens. An interconnecting arrangement, rotatably mounted on themounting arrangement, engages the focusing ring to move therewith. Avariable resistance system is mounted on the two arrangements and isvaried by movement of the interconnecting arrangement relative to themounting arrangement. The variable resistance system includes anadjustable member which is movable between a number of positions. In oneposition the variable resistance system exhibits one range ofresistances corresponding to one type of lens when the interconnectingarrangement is moved. In other positions the variable resistance systemexhibits other ranges of resistances each corresponding to lenses ofother aperture ratios and focal lengths. An electrical system connectedto the variable resistance system responds to the value of theresistance exhibited and controls the diaphragm of the camera forautomatic flashlight photography.

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SEEHHF I FIG. 7 FIG. 8

FIG. 9

H3 R "R1 5 66 uhm asb uwiam) 2 111; 1. 1m) l m hi 0 5 A V I i c? c'scsd4 c3 c2 c1 INVENTOR 739/20 NIIIIY/ 010 m whale/fr ATTORNEY LENSATTACHMENT FOR FLASH-LIGHT PHOTOGRAPHING The present invention relatesto a lens attachment for flash-light photographing, and particularly, alens attachment for flash-light photographing, which is additionallyfitted to a photographic lens for automatic flash-light photographing.

In case of flash-light photographing, such an auxiliary light means as aflash bulb, a strobo lamp or the like is made flash synchronously withthe operation of a camera shutter to illuminate the object to besnapped, so that a good exposure can be obtained even for the darkobject to be snapped in flash-light photographing. In such case offlash-light photographing, the quantity of light to be obtained byflashing of such as a strobo bulb, used for an auxiliary illuminationlight, namely the guide number has various values, so that each time ofphotographing it becomes necessary on the camera side to calculate thenumber GN and the distance D to the object to be snapped in order to getthe diaphragm F GN/D.

It is very troublesome to calculate as above each time a photograph istaken. Therefore, as a method to get rid of this defect, it has hithertobeen suggested that as shown in for example U.S. Pat. Nos. 3,074,331,3,128,168, 3,134,315, 3,169,464, 3,198,096, 3102,461, BP 920,826, U.S.Pat. Nos. 3084,605, 3,087,397, BP 984,435, DP 1,170,774, FP 1340577,U.S. Pat. No. 3075,442, DP 1173,334, a mechanical calculation mechanismis equipped inside a camera or a lens tube and is so constructed as tofigure out the diaphragm value or the distance value for a good exposurewhen the distance or the diaphragm is adjusted by adjustment of theguide number. It is well-known as another suggestion to be enumeratedthat as shown in for example Japanese Patent Publication No. Sho-3-9-20275 and German Patent No. 1927498, the movable slider of a variableresistor, set in the lens, is made variable in interlocking with thedistance ring of a photographic lens for a camera, so that thecalculation is electrically performed by the electric resistance of saidresistor; the result of the calculation being indicated by the swing ofthe indicator of a meter to get the diaphragm value for a good exposure.

According to all of the above-mentioned prior arts, the combination ofdistance and diaphragm values is calculated and adjusted from the guidenumber of an auxiliary light in a special camera or lens, equipped witha calculation mechanism in the camera or the lens tube. Therefore, thecamera or lens has been so constructed as to be used for a specialmachine.

However, in order to equip such a calculation mechanism in a popularcamera, it is necessary to remodel the camera or lens essentially. Itwas substantially impossible to equip such a calculation mechanism in alens built-in type camera. In case of a camera, in which a lens tube anda camera body can be separated and interchangeable lenses, havingvarious kinds of open diaphragm values are used, it is impossible tomake it able to take a flash-light photograph with any of theinterchangeable lenses. The reason is that it is impossible to calculateexactly at the time of the automatic flash-light photographing, if theopen diaphragm values are not set in the calculation mechanism for everykind of interchangeable lenses. There is such a defect that even if thecalculation mechanism is fitted to the camera body to receive an opendiaphragm value signal from the side of the interchangeable lens to beused, it is necessary to remodel both sides of the camera and the lensdrastically.

In case of a single-lens reflex camera, having interchangeable lensesused, when the distance ring of the interchangeable lens is adjusted, arange information is not transmitted as a mechanical displacement to theside of the camera body. Therefore, if the calculation mechanism iscontained only on the side of the camera body and the side of theinterchangeable lens is not remodelled, it cannot serve for theautomatic flashlight photographing. Both the camera and the lens must besubstantially remodelled.

As above-mentioned, it is necessary for an existing camera to remodelthe camera and/or the lens substantially in order to take an automaticflash-light photograph. But such a remodelling is essentiallyimpossible. Therefore, a camera or lens must be specially constructedfor automatic flash-light photographing.

It is the object of the present invention to eliminate theabove-mentioned conventional defect and to provide a lens attachment,which is fitted additionally to the end of a lens so that it becomesable to take an automatic flash-light photograph.

Another object of the present invention is to provide a lens attachmentfor automatic flash-light photographing, comprising that a variableresistor is set in the attachment, fitted additionally to the end of thelens and said resistor is made variable in interlocking with theadjustment of the distance ring of the lens, so that the resistancevalue of said resistor can be caught as a range information.

The other objects of the present invention may be made clear from thedetailed description of embodiments of the present invention inreference to the attached drawings.

FIG. l is a perspective general view of a camera, when a lens attachmentaccording to the present invention is fitted to an interchangeable lenstype single-lens reflex camera;

FIG. 2, a perspective front view of a lens attachment;

FIG. 3, a perspective rear view of a lens attachment;

FIG. 4, a cross section view of the lens attachment, shown in FIGS. 1and 2;

FIG. 5, a partly sectional view of the lens attachment, shown in FIG. 3;

FIG. 6, a schematic view of the main part of a lens attachment accordingto the present invention;

FIGS. 7 and 8, respectively a side view and a front view of the mainpart of a lens tube, fitted with a lens attachment according to thepresent invention; and

FIG. 9, an assembly drawing for the main part of a lens attachmentaccording to the present invention.

DESCRIPTION OF EMBODIMENT In FIG. 1, l is a single-lens reflex camerabody; 2, a strobo, equipped to the accessary shoe, which is attached tothe camera body l;3, an interchangeable lens, attached to'the camerabody 1; 3,, a diaphragm adjustment ring, equipped on the lens 3; 3 arange adjustment ring, equipped on the lens 3; 4, an attachment forautomatic flash-light photographing; and 4,, a lead connection of theattachment and connected with an outer terminal on the side of thecamera body 1. The strobo 2 is so constructed that when the strobo 2 isfixed to the shoe 1, of the camera, the leg 2, of the strobo iselectrically connected with the connecting terminal for asynchrocontact, equipped on the shoe 1,.

When the lens attachment 4 according to the present invention is notfitted, the camera 1 is fitted a with the lens 3 and the strobo 2 toperform common strobo auxiliary light photographing. In this case, it isnecessary to figure out the diaphragm value from the guide number of thestrobo 2 and the distance, indicated by the distance ring 3 of the lens3. It is impossible to take the socalled automatic flash-lightphotograph. If the attachment 4 is fitted to the end part of the lens 3,it becomes possible to take an automatic flash-light photograph asdescribed here-in-after.

The attachment 4 is shown in detail in FIGS. 2 to 5. In each drawing, 5is an attachment case, constructed in a channel shape and also made socircular as to surround the end part of the lens tube, which will beexplained below. 6 is a thumb nut, pivoted with a shaft 6, rotatably onthe front face of the case 5 for adjusting the open diaphragm value ofthe lens; and 6 a movable contact, fixed to the shaft 6,. The diaphragmadjustment thumb nut 6 is, as shown in FIG. 2, so turned as to make theindex correspond to each index diaphragm indication in order to beavailable for-various lenses, having different open aperture values. Itis loosely fixed by a click mechanism (not shown in the drawing). 7 is abayonet plate, composed in one piece with the case 5 and having notchedportions 7,, 7 and 7 to be inserted with bayonet claws as shown in FIG.5. 9 is a confronting holder, made in one piece with the case 1 andconfronting the bayonet plate with a stepped portion, to leave a space10 against said plate 7, so that the bayonet claws on the lens side areinserted into the space to be held. 11 is a rotary plate, made socircular as to cover the rear opening part of the case 5 and having theperipheral edge held ratatably by fixing screws 12,, 12 and 12;, on thebayonet plate 7. 11' is a covering plate for the rotary plate 11. 13 isa distance ring holding member, inserted in a concave groove 14 of therotary plate 11 and held slidably in the direction of theoptical axis.It is bent in a L shape as shown in FIG. 4 and has a slot 13 made on itsbent part 13,. The longitudinal length of the slot 13 should be such asufficient length that when the pin of the distance ring of .the lens isinserted in said slot as mentioned hereinafter, the pin is removed inthe direction of the optical axis according to the degree of the lens tobe drawn out, but the pin can freely move in said slot 13 with asufficient clearance.

15 is a check lever, having the end portion engaged with a notchedgroove 13,, made on the side of the holding member 13 and besides,pivoted with a pivot journal 16, fixed to the rotary plate 11. When theattachment 4 is fitted to the lens tube, the interlocking pin on thedistance ring of the lens may be made to change in height, but the pincan be engaged or disengaged by this lever. 17 is a printed plate,contained in the case 5 and connected with the rotary plate 11 ininterlocking with an interlocking pin 18 as shown in FIG. 6. 19 is astationary contact, fixed through an isolated base plate 20 to theinside of the case 5 and always pressed to the printed plate 17. Asshown in thedevelopment of FIG. 9, the printed plate 17 is provided withfixed resistors R to R firmly arranged in its circumferential portion.Conductors C to C are printed in wiring for connecting the respectiveresistors succes-' sively in series with the adjoining.

Further, the conductors C C C C C C and C are printed in wiring inparallel to the respective conductors C to C, with the one-stepdisplacement in a radial direction. Each conductor is step-wisedisplaced in a radial direction in parallel to the conductors C to C sothat a conductive part is formed with a successive lag. By the rotationof the beforementioned open diaphragm value adjustment thumb nut 6, theindex is made to correspond to the diaphragm value index, stamped on theouter surface of the case 5. Then, the movable contact 6 is removed bymeans of the shaft 6, to the position, shown with a dotted line in FIG.9, so that the position of the contact 6 is adjusted corresponding tothe open diaphragm value of the lens. A fixed resistor, having an almostsimilar resistance value is available for the respective resistors R, toR 21 is a clamp releasing lever, protruded from the case 5 to beoperated from outside and pressing a clamp lever 22. 23 is a signaltransmission cable, connected with the sliders 6 and 19. FIGS. 7 and 8are schematic views of the end portion of a lens tube which is appliedwith an attachment 4, having the abovementioned construction. In thedrawings, 32 is a distance ring for adjustment of the range of a lenstube; 33, an interlocking pin, attached to the distance ring 32; and 34,an adaptor fixture, attached to the end of the lens tube and having athree-clawed bayonet part 35. When the distance ring 1 is turned in thedirection of an arrow to adjust the range from the infinite distance ofthe object to be snapped towards the near distance, the adaptor fixturejuts straight out in the axial direction of the distance ring 1. 36 is aclamp groove, made in the bayonet part 35. Y

The case that an attachment, constructed as above for automaticflash-light photographing, is fitted to a camera to take an automaticflash-light photograph, shall be explained as an example, as follows;

7 First, the bayonet 3,, is inserted in the bayonet receiving grooves 7,to 7 as the check lever 15 on the rotary plate 11 being pushed. Theattachment 4 is turned at a prescribed angle to be mounted on theuniversal lens tube, having the interlocking pin 33 in the distance ring32. The lens tube 3 and the attachment 4 are firmly fixed by therespective bayonetparts 35 and 7, the clamp 22 and the clamp groove 36,and a spring (not shown in the drawing), which acts on the clamp 22.Next, the check lever 15 is pushed to release the L- shaped member 13 ina diametrical direction from the engagement with the interlocking pin33. In this condition, the interlocking pin 33 of the distance ring 32is fitted to the long groove 13 of the L-shaped member 13, and the checklever 15 is released from pushing. Then, the L-shaped member 15 isrestored to be engaged with the interlocking pin 3 because the spring isacting to the check lever 15. Thus, the distance ring 3 of the lens tubeis interlocked with the rotary plate 11 of the adaptor. The clickoperation of the open diaphragm value adjustment thumb nut 6 can beselectively applied to several kinds of lenses, having a different focaldistance and open diaphragm value. Therefore, it is set to the lens tube3, interlocking with the attachment 4. Finally, the cord 23, having twoterminals of a movable contact 6 and a contact brush 19, is connected inparallel with CdS of the exposure control circuit 21 of the camerathrough a change-over switch Sw. In order to equip the attachment 4, thebody of the attachment 4 is turned at a certain angle, as the clamp pushbutton 21 and the check lever being pushed.

In case of flash-light photographing, the switch SW is changed over fromthe contact a of the exposure meter circuit to the contact b of theflash circuit. (FIG. 5) Then, the guide number is set and the distancering 1 of the tube is operated. When the range is adjusted to the objectto be snapped, the printed plate 17 is rotated by the rotary plate 11and the fixing pin 18. The resistance value inside the attachment ismade to change corresponding to the distance. The diaphragm value isautomatically calculated. In the needle-type camera, the needle is setto the diaphragm control device of the lens tube, so that the irisaperture is determined, while in the EB camera, the iris aperture isdetermined at the same time when the diaphragm value is calculated bythe EB mechanism.

When light is measured in a camera of the so-called TTL open exposuremeasuring system, attached with a kind of lens, having different open Fnumbers, the ammeter deflects at a different angle, as a result of thedifference of the passing quantity of light, even though the same objectis snapped. Accordingly, in this type of camera, the ammeter is turned(absolute value signal type) or the diaphragm index of the finder ismoved (system of open F numbers being evenly arranged) by a mechanicalor manual operation for compensation. It is necessary to change overexactly for theabovementioned compensation on the camera side in case offlash-light photographing, because the diaphragm value for the distancefrom the object to be snapped must be always same without regard to theopen F number of the lens.

In the apparatus according to the present invention, the change-overeffect is obtained for the difference of the open F number of the lens,by that the conductors (C to C and (C to C are placed on the printedplate 17 with a lag for a series of resistance values according to thedistance from the object to be snapped. For example, as shown in FIG. 9,the F 2 lens has a larger resistance value by one step at the samedistance of 2 m from the object to be snapped, as compared with the F1,4 lens, having the same focal distance. The resistance valuecorresponds to that of the camera, having a F 1,4 lens, at the distanceof 2.8 m from the object to be snapped. Similarly, the resistance valueof a F 2.8 lens, having another focal distance, is large by two stepsand corresponds to that of a F 1.4 lens at the distance of 4 m. 4

As the present invention is composed as above, flash interlocking orautomatic flash photographing can be performed for a plurality ofcameras, having the same indication current value of an exposure meter,in combination of a plurality of lens, having different focal distanceand open diaphragm values. The simplification and automation of flashphotographing as well as the enlargement of a flash photographic rangeare also resulted very conveniently.

What is claimed:

1. For an automatic flashcamera having an automatic diaphragm controland a photographic lens with a rotatable focusing ring, a lensattachment, comprising mounting means for detachably mounting theattachment at the end of the lens, interconnecting means rotatablymounted on said mounting means and engageable with the focusing ring,variable resistance means mounted on said mounting means-and saidintercon necting means, said resistance means being variable by movementof said interconnecting means with the focusing ring and having anadjustable member which is movable between a plurality of positions,said variable resistance means exhibiting one range of resistancescorresponding to one type of lens when the member is in one position andthe interconnecting means is moved relative to the mounting meansthrough a given path, said variable resistance means exhibiting anotherrange of resistances corresponding to another type of lens when themember is in another position and the interconnecting means is movedrelative to the mounting means through a path corresponding to the onepath, electrical means connected with said variable resistance means andcoupled to said diaphragm control means for adjusting the diaphragm onthe basis of an electrical resistance value based upon the rotation ofthe focusing ring and the position of said member, said member beingadjustable to a position causing said resistance means to exhibit arange of values corresponding to the type of lens.

2. An attachment as in claim 1, wherein said variable resistance meansincludes a plurality of conductive contact means extending along aplurality of separate paths and mounted on one of said interconnectingmeans and said mounting means, said resistance means further including aslider mounted on the other of said mounting means and saidinterconnecting means and contacting one of said contact means on thebasis of the position of said member and movable along one of the pathswhen said interconnecting means moves with respect to said mountingmeans and varying the resistance exhibited by said resistance means onthe basis of the type of lens being used and the position of thefocusing ring.

3. An attachment as in claim 1, wherein said variable resistance meansextends along a circular path.

4. A system as in claim 2, wherein said resistor means extend alongcircular paths.

5. An attachment as in claim 2, wherein each of said contact meanscomprises an insulating base plate, a plurality of contact stripsextending along the path, said strips being separated from each other, aplurality of resistances connected between said contact strips, thelocation of said contact strips causing said slider to be connected todifferent ones of said resistances depending upon the position of saidmember and the focusing of said ring, and wiring means connecting saidresistance means to said circuit means.

6. A camera, comprising a camera body, an interchangeable lens, anadjustable focusing ring on the lens, mounting means for detachablymounting the attachment at the end of the lens, interconnecting meansrotatably mounted on said mounting means and engageable with thefocusing ring, variable resistance means mounted on said mounting meansand said interconnecting means, said resistance means being variable bymovement of said interconnecting means with the focusing ring and havingan adjustable member which is movable between a plurality of positions,said variable resistance means exhibiting one range of resistancescorresponding to one type of lens with the members in one position andthe interconnecting means is moved relative to the mounting means, saidvariable resistance means exhibiting another range of resistancescorresponding to another type of lens when the member is in anotherposition and the interconnecting means is moved relative to the mountingmeans, electrical means connected with said variable resistance meansand coupled to said diaphragm control means for adjusting the diaphragmon the basis of an electrical resistance value based upon the rotationof the focusing ring and the position of said member, said member beingadjustable to a position cause said resistance means to exhibit a rangeof values corresponding to the type of lens.

7. A camera as in claim 6, wherein said variable resistance meansincludes a plurality of conductive contact means extending along aplurality of separate paths and mounted on one of said interconnectingmeans and said mounting means, said resistance means further including aslider mounted on the other of said mounting means and saidinterconnecting means and contacting one of said contact means on thebasis of the position of said member and movable along one of the pathswhen said interconnecting means moves with-respect to said mountingmeans so as to vary the resistance exhibited by said resistance means onthe basis of the type of lens being used and the position of thefocusing ring.

8. A camera as in claim 6 wherein said variable resistance means extendsalong a circular path.

9. A system as in claim 7, wherein said resistor means extend alongcircular paths.

10. A camera as in claim 7, wherein each of said resistor meanscomprises an insulating base plate, a plurality of contact stripsextending along the path, said strips being separated from each other, aplurality of I resistances connected between said contact strips, the

location of said contact strips causing said slider to be connected todifferent ones of said resistances dependtance means to said electricalmeans.

1. For an automatic flash camera having an automatic diaphragm control and a photographic lens with a rotatable focusing ring, a lens attachment, comprising mounting means for detachably mounting the attachment at the end of the lens, interconnecting means rotatably mounted on said mounting means and engageable with the focusing ring, variable resistance means mounted on said mounting means and said interconnecting means, said resistance means being variable by movement of said interconnecting means with the focusing ring and having an adjustable member which is movable between a plurality of positions, said variable resistance means exhibiting one range of resistances corresponding to one type of lens when the member is in one position and the interconnecting means is moved relative to the mounting means through a given path, said variable resistance means exhiBiting another range of resistances corresponding to another type of lens when the member is in another position and the interconnecting means is moved relative to the mounting means through a path corresponding to the one path, electrical means connected with said variable resistance means and coupled to said diaphragm control means for adjusting the diaphragm on the basis of an electrical resistance value based upon the rotation of the focusing ring and the position of said member, said member being adjustable to a position causing said resistance means to exhibit a range of values corresponding to the type of lens.
 2. An attachment as in claim 1, wherein said variable resistance means includes a plurality of conductive contact means extending along a plurality of separate paths and mounted on one of said interconnecting means and said mounting means, said resistance means further including a slider mounted on the other of said mounting means and said interconnecting means and contacting one of said contact means on the basis of the position of said member and movable along one of the paths when said interconnecting means moves with respect to said mounting means and varying the resistance exhibited by said resistance means on the basis of the type of lens being used and the position of the focusing ring.
 3. An attachment as in claim 1, wherein said variable resistance means extends along a circular path.
 4. A system as in claim 2, wherein said resistor means extend along circular paths.
 5. An attachment as in claim 2, wherein each of said contact means comprises an insulating base plate, a plurality of contact strips extending along the path, said strips being separated from each other, a plurality of resistances connected between said contact strips, the location of said contact strips causing said slider to be connected to different ones of said resistances depending upon the position of said member and the focusing of said ring, and wiring means connecting said resistance means to said circuit means.
 6. A camera, comprising a camera body, an interchangeable lens, an adjustable focusing ring on the lens, mounting means for detachably mounting the attachment at the end of the lens, interconnecting means rotatably mounted on said mounting means and engageable with the focusing ring, variable resistance means mounted on said mounting means and said interconnecting means, said resistance means being variable by movement of said interconnecting means with the focusing ring and having an adjustable member which is movable between a plurality of positions, said variable resistance means exhibiting one range of resistances corresponding to one type of lens with the members in one position and the interconnecting means is moved relative to the mounting means, said variable resistance means exhibiting another range of resistances corresponding to another type of lens when the member is in another position and the interconnecting means is moved relative to the mounting means, electrical means connected with said variable resistance means and coupled to said diaphragm control means for adjusting the diaphragm on the basis of an electrical resistance value based upon the rotation of the focusing ring and the position of said member, said member being adjustable to a position cause said resistance means to exhibit a range of values corresponding to the type of lens.
 7. A camera as in claim 6, wherein said variable resistance means includes a plurality of conductive contact means extending along a plurality of separate paths and mounted on one of said interconnecting means and said mounting means, said resistance means further including a slider mounted on the other of said mounting means and said interconnecting means and contacting one of said contact means on the basis of the position of said member and movable along one of the paths when said interconnecting means moves with respect to said mounting means so as to vary the resistance exhibited by said resistance Means on the basis of the type of lens being used and the position of the focusing ring.
 8. A camera as in claim 6 wherein said variable resistance means extends along a circular path.
 9. A system as in claim 7, wherein said resistor means extend along circular paths.
 10. A camera as in claim 7, wherein each of said resistor means comprises an insulating base plate, a plurality of contact strips extending along the path, said strips being separated from each other, a plurality of resistances connected between said contact strips, the location of said contact strips causing said slider to be connected to different ones of said resistances depending upon the position of said member and the focusing of said ring, and wiring means connecting said resistance means to said electrical means. 